A curable liquid rubber composition including at least one liquid polyene component and at least one heat activated crosslinking agent. The liquid polyene component may be a single polyene or a blend of polyenes. In one embodiment, the liquid polyene component may contain on a molar basis, at least one monomer that results in at least 45 molar percent of C2-C13 pendant groups. In another embodiment, the liquid polyene component may contain on a molar basis at least one monomer that results in at least 20 molar percent of C2-C5 pendant groups, and at least one monomer that results in at least 7 molar percent of C6-C13 pendant groups. After curing, the liquid rubber composition may have a loss factor greater than 0.51, a maximum loss factor temperature greater than −10° C., and a swelling ratio in toluene from 40% to 170% by weight.